Variable area exhaust nozzle



March 29, 1966 A. KURTx ETAL VARIABLE AREA EXHAUST NOZZLE 6 Sheets-Sheet1 NUTM.

INVENTORS ALEXANDER KURT! March 29, 1966 A. KURT: ETAL 3,243,126

VARIABLE AREA EXHAUST NOZZLE Original Filed Jan. 4, 1961 6 Sheets-Sheet2 I 1 l l l rr k l l l INVENTORS ALEXANDER KURT! EVERETT A- JOHNSTONEvy/UWM? AT'TO RNEY March 29, 1966 A. KURTI ETAL VARIABLE AREA EXHAUSTNOZZLE 6 Sheets-Sheet. 5

Original Filed Jan. 4, 1961 INVENTORS ALEXANDER KURT! EVERETT A..JOHNSTON BYWM/ ATTO RNEIY March 2'9, 1966 A. KURTI ETAL VARIABLE AREAEXHAUST NOZZLE 6 Sheets-Sheet 4 Original Filed Jan. 4, 1961 ALEXANDERBYY/ NNY

March 29,Y 1966 A. KURTI ETAL 3,243,126

VARIABLE AREA EXHAUST NOZZLE original Filed aan. 4, 1961 e sheets-sheets FIGJB j a //fZ ALEXANDER KURT! EVERETT A JOHNSTON @T/Mm mfg# HMMATTORNEY March 29,' 1966 A. KURTI E'rAl. 3,243,126

VARIABLE AREA EXHAUST NOZZLE Original Filed Jan. 4, 1961 6 Sheets-Sheet6 INVENTORS ALEXANDER KURT! EVERETT A JOHNSTON ATTORNEY United StatesPatent O 3,243,126 VARIABLE AREA EXHAUST NOZZLE Alexander Kurti, WestHartford, Coun., and Everett A.

Johnston, Springfield, Mass., assignors to United Aircraft Corporation,East Hartford, Conn., a corporation of Delaware Continuation ofapplication Ser. No. 80,582, Jan. 4, 1961.

This application Sept. 18, 1963, Ser. No. 310,192 8 Claims. (Cl.Z39-265.39)

This is a continuation application of United States patent applicationSerial No. 80,582 on improvements in Exhaust Nozzles, by Alexander Kurtiand Everett A. Johnston, led January 4, 1961, now abandoned.

It is an object of this invention to teach a variable area exhaustnozzle which is so shaped and which has pivotal flaps actuatable so thatthe exhaust nozzle is either convergent or convergent-divergent.

It is a further object of this invention to teach a variable areaexhaust nozzle which is light in weight and which is capable ofwithstanding high operating temperatures.

It is a further object of this invention to teach a variable areaexhaust nozzle in which the exhaust nozzle flaps and the ap support andactuating means are iiexibly supported from the exhaust duct to permitsubstantial relative thermal expansion therebetween.

It is a further object of this invention to teach an exhaust nozzlewherein cooling air may be passed over the ap actuating and supportmeans.

It is a further object of this invention to teach an exhaust nozzlewhich can be removed from the engine by the removal of a few accessiblebolts.

Other objects and advantages will be apparent from the specification andclaims and from the accompanying drawings which illustrate an embodimentof the invention.

FIG. 1 is an external View of a modern aircraft engine which generatesthrust by discharging exhaust gases to atmosphere and which utilizes ourexhaust nozzle;

FIG. 2 is an enlarged cross-sectional showing of the exhaust nozzledepicted in FIG. 1;

FIG. 3 is a partial showing of the exhaust nozzle shown in FIG. 2 asviewed from line 3-3;

FIG. 4 is a developed view taken along line 44 of FIG. 3 with theexhaust nozzle aps and unison gears removed to show the exhaust nozzleap support mechanism more clearly;

FIG. 5 is a view, partially broken away, as viewed from line 5-5 of FIG.4;

FIG. 6 is a cross-sectional view similar to FIG. 2 but in a positionbetween flaps to illustrate the structure to which the flaps arepivotally attached;

FIG. 7 is an enlarged View taken along line 7-7 of FIG. 6;

FIG. 8 is a showing of the unison ring as Viewed from line 8-8 of FIG.7;

FIG. 9 is an enlarged view taken substantially along line 9 9 of FIG. 2;

FIG. 10 is a View as seen from line 10-10 of FIG. 9;

FIG. 1l is a view as seen from line 11-11 of FIG. l0;

FIG. 12 is a view taken along line 12-12 of FIG. 2 -to illustrate themechanism by which the ap support and actuating means are pivotallyattached to the exhaust gas duct;

FIG. 13 is a perspective showing of the exhaust nozzle with the flapsclosed; and

FIG. 14 is a perspective showing of the exhaust nozzle with the flapsopen.

Referring to FIG. 1 we see modern aircraft jet type engine 10 which maybe of the type fully disclosed in U.S. Patent Nos. 2,711,631v and2,747,367. Engine 10 comprises compressor section 12, burner section 14,turbine section 16, afterburner 18, which may be of the type rice fullydisclosed in U.S. Patent Nos. 2,735,262, 2,819,587, 2,846,841 and2,846,842 and our exhaust nozzle 20. Engine 10 is preferably of circularcross section and concentric about axis 22.

In operation, air enters the inlet 24 of engine 10, is compressed inpassing through compressor section 12, has heat added thereto in passingthrough burner section 14 and has energy extracted therefrom to drivecornpressor section 12 while passing through turbine section 16. Theengine gases, after leaving turbine 16, enter afterburner section 18where they are re-heated as fully disclosed in the above-mentionedafterburner patents and discharged to atmosphere in a thrust-generatingfunction through our variable area exhaust nozzle 20.

As best shown in FIG. 2, our variable area exhaust nozzle 20 comprisesafterburner duct 26, which together with the remainder of exhaust nozzle20, is of circular cross section and concentric about axis 22.Afterburner duct 26, which may include cooling liner 28, defines fixedoutlet 30 through which the engine exhaust gas must pass. Strengtheningring 32 may be attached to the afterburner duct 26 by any convenientconnecting means such as nut and bolt arrangement 34 and serves tostrengthen duct 26 and to strengthen and support liner 28 While definingregulating ports such as 36 through which the cooling air which may beprovided from any convenient source such as a compressor 12 and whichpasses between cooling liner 28 and afterburner duct 26 is dischargedwith the engine exhaust gases through outlet 30.

Our exhaust nozzle 20 further includes fixed nozzle member 38 which isradially spaced from duct 26 and extends from and axially downstreamthereof and which has smooth inner surface 40 which diverges withrespect to axis 22 and smooth outer surface 42 which converges withrespect to axis 22 and which joins inner surface 40 at circular outer 44to define a second fixed exhaust outlet. Nozzle fixed member 38 hasliexible and radially inward directed ange 46 extending inwardly fromthe outer wall 42 thereof and further has flexible flange 48 positionedaxially forward of flexible liange 46 and which is also positioned bythe outer wall 42. It will hereinafter be shown that the exhaust nozzlewill be flexibly supported from afterburner duct 26 through actuatingmechanism soon to be described by connection to flexible flanges 46 and48. It will be noted that fixed nozzle member 38 is spaced radially fromafterburner duct 26 to define an annular space 50 therebetween throughwhich cooling air, such as ram air, may pass over the ap supporting andactuating apparatus immersed therein.

A plurality of pivotal aps 52, preferably eight, are positionedcircumferentially about fixed outlet 30 and are sealably connectedthereto through flexible seal ring 54 which may comprise a plurality ofabutting and flexible fingers attached to duct 26 through rivets S6.Flaps 52 may be pivoted to an inner pivot position as shown in solidlines in FIGS. 2 and 3 wherein the inner surface 58 thereof defines aconvergent exhaust nozzzle with duct 26. It will be noted as best shownin FIG. 3 that with iiaps 52 in their inner pivot position, their sidesurfaces such as 60 and 62 are in abutting relation so as to prevent theliow of exhaust gas therebetween and that the after end of the innersurface 58 thereof defines convergent exhaust nozzles throat 64. Flaps52 may also be pivoted to their outer pivot position shown in phantom inFIG. 2 wherein the inner surface 58 thereof extends between the afterend of duct 26 and the forward end of the inner surface 40 of lixedmember 38 to cooperate therewith to define a convergent-divergentexhaust nozzle having throat 30 and maximum outlet area 44 such thatsurfaces 58 and 40 define a continuous divergent expansion surfaceagainst which exhaust gas may expand in a thrust-generating fashion. Itwill further be noted that with flaps 58 in their inner position,cooling air is free to pass through annular space 50 but that with flaps52 in their outer pivot position, this cooling gas passage is restrictedsuch that the only flow is between and around aps 52.

Flaps 52 are pivotally connected to xed member 38 in a fashion to bedescribed hereinafter and are caused to pivot inwardly and outwardly toand between their solid line and phantom line FIG. 2 positions by theco-action of pressurized cylinder piston arrangement 66, preferably onefor each ap, and linkage arrangement 68, which includes expandable links70 and 72which are pivotally connected by any convenient connectingmeans but preferably by shaft 74 passing therethrough which also servesas a journal for the rollers of roller unit 76. Roller unit 76 bearsagainst and `co-acts with contoured cam surface 78 of cam mechanism 80.A retaining plate 82 is connected to cam mechanism 80 by any convenientmeans such as connecting mechanism 84 (as shown in FIG. 11) to retainthe rollers of roller unit 72 within cam mechanism 80 and againstcontoured surface 78 thereof. As roller unit 76 is caused to moveforwardly and rearwardly along cam surface 78 by actuating cylindermechanism 66, tiaps 52 are caused to pivot inwardly and outwardly due tothe co-action of links 70 and 72.

Actuating cylinder-piston unit 66 comprises actuating cylinder 86 withdouble acting piston unit 88 therein. As best shown in FIG. 12,cylinder-piston unit 66 is pivotable about pivot pins 90 and receivesactuating uid through either line 92 or 94 to cause double acting anddouble piston unit 88 to reciprocate. When actuating fluid entersthrough line 92, it enters port 96 and ows therefrom into actuatingchamber 98 and through passage 108 into actuating chamber 102 so thatthe actuating uid is acting against both pistons 104 and 106 to causelink unit 68 to force roller unit 76 rearwardly, thereby causing flaps52 to pivot to their inner or solid line FIG. 2 or FIG. 3 or FIG. 13positions. When actuating uid enters through line 94, it enters cylinderpiston unit 66 through aperture 108 and enters chamber 110 only so thatroller unit 76 is pulled forwardly along contoured surface 78 bylinkag-e unit 68 to cause aps 52 to pivot to their outer or phantom FIG.2 position. It will therefore be noted that while actuatingcylinder-piston unit 66 is double acting, it has a higher actuatingforce available to close the exhaust nozzle, that is, to cause aps 52 topivot inwardly against the force of the exhaust gases than is availableand necessary to cause aps 52 to pivot outwardly with the aid of theexhaust gas pressure.

Cam mechanism 80 is part of spaced plate unit 112 which attaches toexible ange 46 through ared ange 114 which includes bolt holes 116 and118 and which attaches to flange 46 by any convenient connecting meanssuch as nut and bolt units 49 and 51.

At its other end, spaced plate unit 112 consists of spaced plates 120and 122, each of which is pivotally attached to afterburner duct 26, andmore particularly to support frame 124 thereof through nut and boltarrangements 126 and 128.

Support frames 124 extend axially along duct 26 as best shown in FIG. land are spaced circumferentially thereabout between spaced plate units112 as best shown in FIG. 9 such that frame units 124 and spaced plateunits 112 cooperate to dene a support ring or hoop 125 extendingcircumferentially about after burner duct 26.

It will be noted, as best shown in FIG. 9, that actuating cylinder andpiston unit 66 is positioned between the spaced plates 12) and 122 ofspaced plate unit 112 and is pivotally attached thereto, as best shownin FIG. 12 by pivot pins 90 such that actuator 66 is capable of pivotingduring the actuation of aps 52. Preferably, an insulating layer 121 ispositioned on unit 66.

Flaps 52 are pivotally attached to flap pivot mechanisms 130 each ofwhich, as best shown in FIGS. 3 and 4, is attached to plate member 132by connecting means such as bolt and nut arrangements 134, 136 and 138.Plate mechanism 132 extends between anges 114 of double plate units 112and are alternately positioned therewith circumferentially about lixednozzle member 38 and are connected to unit 112 by nut and boltmechanisms 49 and 51 such that plate members 132 and spaced platemembers 112 form a continuous hoop 113 around xed nozzle member 38,which hoop is attached to flexible ange 46 by bolts 49 and 51 and toflexible tiange 48 by a slide fit connection, as best shown in FIG. 5.

Flap pivot mechanism consists of two members, 140 and 142, which arejoined through nut and bolt arrangements 144, 146 and 148. Pivotmechanism 130 is split into two parts and 142 to permit the reception inspherical socket 150 thereof, of spherical journal 152, which receivespivot pins 154 of gear plates 156 and 158, which gear plates alsoinclude pilot pins and 162, which are received in recesses in theflanged side surfaces 62 and 60 of adjacent flaps 52. In this fashion,flaps 52 are pivotally attached to flap pivot unit 130 which is in turnattached to support ring 113, which is formed by plate units 132 andspaced plate units 112, and which is also attached to the xed nozzlemember 38. Fitted member 67 joins unit 130 to flanges 46 and 48.

Gear plate units 156 and 158 carry mating gears 164 and 166 whichperform the function of causing unitary pivot action between theplunality of aps 52.

In view of the description just completed, it will be obvious to thoseskilled in the art that nozzle xed member 38, aps 52, aip pivotal units130, actuating mechanism 66 and all related parts are flexibly supportedfrom duct 26 by spaced plate units 112 which are pivotally attached toduct 26 at support ring 125 and which are flexibly connected to memlber38 by support ring 11'3. In View of this flexible support connect-ion,relative thermal growth is permissible between the extremely hot duct 26and the exhaust nozzle 20, which exhaust nozzle operates in a muchcooler region due to the passage of cooling air there/over. Further,exhaust nozzle 20 may be removed from engine 10 merely by disconnectingthe 16 bolts 1-26 and 128.

It is to be understood that the invention is not limited to the specificembodiment herein illustrated and described but may be used in otherways without departure from its spirit as defined by the followingclaims.

We claim:

1. In a jet engine Variable area exhaust nozzle, an exhaust ductdefining a xed outlet, a plurality of pivotable aps detached from andpositioned substantially equally about said fixed outlet, meanspivotally attached to said duct and pivotally supporting said flaps topermit inward and outward pivotal movement thereof to define a variablearea exhaust outlet, means connecting said flap supporting means to forma ring therewith around said tiaps, a fixed member enveloping said ring,and flexibleI means connecting said fixed member to said ring so thatsaid fixed member, said aps and said ring are supported in suspendedrelation from said duct.

2. In a jet engine variable area exhaust nozzle, an exhaust duct deninga fixed outlet, a plurality of pivotable flaps detached from andpositioned circumferentially about said xed outlet, ring shaped supportmeans encircling and supporting said flaps, a plurality of ap actuatingmechanisms circumferentially positioned about and pivotally attached tosaid duct and also attached to said ring shaped support means therebysupporting said support means and said alps in suspended pivot relationfrom said duct and constituting the sole support for said aps and saidflap support means, a fixed member enveloping said ring shaped supportmeans, flexible means connecting said fixed member to said ring shapedsupport means so that said fixed member, said aps and said ring shapedsupport means are supported in suspended relation from said duct and aplurality of flap actuating cylinders pivotally attached to saidtiapactuating mechyanisrn and to said fiaps to cause inward and outwardpivotal movement thereof to define a variable area circular exhaustoutlet.

3. A jet engine variable area exhaust nozzle off substantially circularcross section and concentric about an axis comprising,

an exhaust duct of substantially circular cross section defining a fixedoutlet, a fixed nozzle defining ring member radially spaced from,encircling and eX- tending from yand axially downstream of said fixedoutlet and including a smooth outer surface converging toward said axisand a smooth inner surface diverging from said axis shaped 4and locatedsuch that an annular space is defined between said duct and said fixedmember, a radially inwardly directed, flexible flange attached to saidfixed member, a plurality of pivotable fiaps positioned substantiallyequally about said fixed outlet, means pivotally solo porting andactuating said flaps to permit inward and outward pivotal movementthereof to define a variable area exhaust outlet so that said flapsdefine `a convergent exhaust nozzle with said duct when in their innerpivot position with said annular space unrestricted thereby and furtherso that said flaps extend between said fixed outlet and said fixedmember inner surtface to define a convergent-divergent exhaust nozzletherewith while blocking said annular space when in their outer pivotposition, said support and actuating means comprising a plurality ofspaced plate members pivotally attached to and circumfere-ntiallypositioned about said duct and attached to said flange so that saidfixed member is pivotably supported from said duct, each of said spacedplate members `comprising spaced plates which are joined at the endattached to said flange to define la contoured cam, double actingcylinder-piston actuating units positioned between and pivotallyattached -to said plates, linkage mechanism joining said actuating unitsto said aps and comprising at least two links, connecting meanspivotally connecting said links and including `a `roller unit contactingsaid cam, first means connecting said spaced plate units to said flange,second means rpivotally connecting said aps to said flange, third meansconnecting said first and second means so that they form a support ringencircling said flaps, said cam and said roller unit and means attachedto said flaps and said second means to cause said fiaps to fpivot inunison.

4. In a jet engine variable area exhaust nozzle, la duct defining afixed exhaust Kgas outlet, a plurality of movable flaps positionedIabout said outlet, first means constituting the sole support Afor saidfiaps and including ring shaped d support means supporting yand`actuating said flaps for movement to define a variable Iarea exhaustoutlet, and second means constituting the sole support for said firstmeans fand `being pivotally connected to said duct and connected to saidfirst means thereby supporting said first means and said fiaps insuspended fashion from said duct.

5. in a jet engine variable are-a exhaust nozzle, a duct defining -afixed exhaust outlet, a plurality of movafble fiaps positioned aboutsaid outlet, means forming a hoop around said flaps land including meansto support said fiaps for movement to define a variable area outlet, andeasily detachable means rpivotally `attached to said duct and flexiblysupporting said hoop means land said flap support means and constitutingthe sole support for said flaps, said hoop means rand said flap supportmeans.

6. In a jet engine variable area exhaust nozzle, ya duct having asupport ring thereafbout and deiining a fixed exhaust outlet, aplurality of movable flaps detached from and positioned about saidoutlet, means :orming a hoop around said flaps fand including means tosupport said fiaps for movement to define a variable area outlet, andeasily detachable means lpivotally attached to said support ring andflexibly attached to :said hoop means so that said fialps and hoop means:are pivotally supported solely from said support ring.

7. In a `jet engine vari-able -area exhaust nozzle which is generally ofcircular cross section and concentric about an axis, yan exhaust ductdefining a fixed circular outlet, a plurality of pivot-able flapsydetached from land positioned circumterentially about said fixedoutlet, flap supp'ort and actuating means comprising 'a support ringeneloping said aps, and plate members Iattached to yand extending tromsaid support ring `and pivotally attached to said exhaust duct so `th-atsaid fiap support uand activating means yare suspended from andpivotally supported solely by said exhaust duct.

8, Apparatus according to claim 7 wherein said fiap support and`actuating means also comprises a plurality of actuating pistonspositioned circumterentially about and pivotally connected to saidexhaust duct.

References Cited by the Examiner UNITED STATES PATENTS 2,714,285 8/1955Geary 60-35.6 2,831,319 4/1958 Geary 60--35.6 2,874,538 2/ 1959 Lauchen60-35.6 2,926,491 3/ 1960 Hyde 60-35.6 2,928,234 3/1960 Brown 60--35.62,931,169 4/ 1960 Glenn 60-35.6 2,984,068 5/ 1961 Eatock 60-35.63,032,974 5/1962 Meyer 60-35.6

MARK NEWMAN, Primary Examiner.

RALPH D. BLAKESLEE, Assislant Examiner.

1. IN A JET ENGINE VARIABLE AREA EXHAUST NOZZLE, AN EXHAUST DUCTDEFINING A FIXED OUTLET, A PLURALITY OF PIVOTABLE FLAPS DETACHED FROMAND POSITIONED SUBSTANTIALLY EQUALLY ABOUT SAID FIXED OUTLET, MEANSPIVOTALLY ATTACHED TO SAID DUCT AND PIVOTALLY SUPPORTING SAID FLAPS TOPERMIT INWARD AND OUTWARD PIVOTAL MOVEMENT THEREOF TO DEFINE A VARIABLEAREA EXHAUST OUTLET, MEANS CONNECTING SAID FLAP SUPPORTING MEANS TO FORMA RING THEREWITH AROUND SAID FLAPS, A FIXED MEMBER ENVELOPING SAID RING,AND FLEXIBLE MEANS CONNECTING SAID FIXED MEMBER TO SAID